Chapter 15
 Immune System - Notes
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 1. Name three main benefits from immune system functioning.

      1. causes inflammation to warn of injurious chemical (e.g., rash on the skin)
      2. eliminates foreign substances and microbes (e.g., bacteria, viruses)
      3. eliminates cancer cells

 2. Name the three special characteristics of the immune system in defending the body and explain the benefits from each characteristic.

     - self-recognition = distinguishes between foreign materials and body components, so it attacks only foreign materials
     - specificity = creates a separate response for each foreign material, so it concentrates resources on existing problems
     - memory = produces residual cells and substances, so it creates faster and stronger responses to subsequent invasion to solve problems faster

 3. Describe the general immune system functions of macrophages and Langerhans cells; types of T-cells; and B-cells

     - macrophages and Langerhans cells
          - process and present antigens to T-cells
          - stimulate T-cell production
     - helper T-cells
          - stimulate all other immune system cells
          - produce positive feedback to enhance response
     - cytotoxic T-cells
          - destroy infected cells and cancer cells
     - delayed hypersensitivity T-cells
          - help destroy abnormal cells
          - cause allergic reactions for warning and for non-specific defense (e.g., inflammation)
     - suppressor T-cells
          - reduce unwanted or excess immune responses
     - B-cells
          - produce antibodies = chemicals that help eliminate harmful materials, bacteria, viruses, and cells

 4. Describe the general features in a primary immune response and secondary immune responses.

     - primary immune response
          - gradual production of many immune cells and much antibody to eliminate the specific undesirable material
          - leaves specific memory cells and antibody for faster and stronger response to subsequent invasions
     - secondary response
          - rapid powerful immune response to second or later invasion
          - produced by residual memory cells and antibodies from previous immune response
          - often fades with time unless re-stimulated periodically

 5. Explain the importance of positive feedback in an immune response.

     - positive feedback assures rapid and adequate production and action of immune cells

 6. Describe the general average effects of aging on immune system functioning.

      - variable but gradual average decline in immune functioning
           - requires more stimulus to be activated
           - requires more time to become active
           - produces less primary response
           - loses memory faster
           - produces less secondary response, especially from new primary responses
      - NOTE: immune system performance declines but it still performs fairly well throughout life unless other factors (many of which are age-related) overwhelm its capacity
     - autoimmune antibodies increase, which seem to indicate declining regulation of immune response but which have no known adverse effects

 7. Name three main reasons for age-related changes in immune system functioning.

     1. decreased thymus functioning (e.g., decr. thymosin production)
     2. decr. lymphocyte production and activation
     3. decr. positive feedback activity (e.g., decr. hT-cell functioning)

 8. Name four specific factors that cause an age-related decrease in the effectiveness of immune system functioning.

     - excess exposure of skin to sunlight (decr. Langerhans cells)
     - cirrhosis
     - malnutrition
     - diabetes mellitus
     - surgery and implants
     - use of anti-inflammatory steroids
     - stress (biological; social, or psychological)
     - excess exposure to microbes or carcinogens (e.g., hospitals)
     - decreased cough and gag reflexes
     - decreased mucociliary escalator function
     -  increased risk of physical injury (e.g., bed sores, fractures);  etc.

 9. Name four problems resulting from age changes in immune system functioning.

     1. decreased inflammation and warning of presence of injurious chemicals
     2. increased risk of new infection (e.g., pneumonia)
     3. increased reactivation of infection such as tuberculosis and shingles
     4. increased risk of cancer
     5. decreased response to vaccines

10. Name three ways to minimize consequences from age-related decreases in immune functioning.

     - avoid excess chronic sun exposure
     - avoid alcoholism
     - get good nutrition
     - exercise
     - minimize use of anti-inflammatory steroids
     - reduce stress
     - avoid exposure to disease-producing microbes, chemicals, and other conditions
     - get vaccinations early and get booster shots as needed
     - augment immune defense functions with other strategies (e.g., antibiotics, chemotherapy)

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